Rose rootstock named &#39;Pronne&#39;

ABSTRACT

A new and distinct rose plant is provided which is particularly well suited for service as a rootstock for a rose scion cultivar. More specifically, when so used the scion cultivar exhibits a propensity to yield an increase in biomass and the promotion of faster bud release when compared to the results achieved when the scion cultivar is grown on its own roots or on a standard rootstock, such as ‘Natal Briar’. Both higher production rates combined with improved quality in the scion variety are facilitated. The new rose plant displays an upright growth habit with vigorous growth. Small single pink changing to near white cup-shaped blossoms are formed having five generally heart-shaped petals. Orange reproductive organs are prominently displayed at the centers of the blossoms. Medium green leaflets with finely serrated margins primarily towards the tips of leaflets and a matte upper surface are displayed.

BOTANICAL/COMMERCIAL CLASSIFICATION

Rosa hybrida/Rose Rootstock

VARIETAL DENOMINATION

cv. Pronne

SUMMARY OF THE INVENTION

The new variety of Rosa hybrida rose rootstock was created by artificialpollination during 2006 at Overberg, The Netherlands, wherein twoseedling parents were crossed which previously had been studied in thehope that they would contribute the desired characteristics. The femaleparent (i.e., the seed parent) was the ‘05-08’ variety (unreleased andnon-patented in the United States). The male parent (i.e., the pollenparent) was the ‘236-1’ variety (unreleased and non-patented in theUnited States).

The parentage of the new variety can be summarized as follows:

‘05-08’×‘236-1’.

The seeds resulting from the above pollination were sown and smallplants were obtained which were physically and biologically differentfrom each other. Selective study resulted in the identification of asingle plant of the new variety.

It was found that the new rose plant of the present invention:

-   -   (a) displays an upright growth habit with vigorous growth,    -   (b) forms small single pink changing to near white cup-shaped        blossoms having five generally heart-shaped petals with the        prominent display of orange reproductive organs at the center of        the blossoms,    -   (c) exhibits medium green leaflets with finely serrated margins        having a matte upper surface, and    -   (d) when used as a rootstock for a rose scion variety exhibits a        propensity to induce an increase in biomass and the promotion of        faster bud release for the scion variety.

The new variety provides an advantageous rootstock for use during theproduction of roses, including cut roses grown under greenhouse growingconditions. When the new variety is utilized as a rootstock, the scionvariety commonly grows more rapidly to yield a greater biomass withthicker and longer stems within a specified period of time. Also, ayield of cut flowers commonly takes place earlier than when a standardrootstock, such as ‘Natal Briar’ (non-patented in the United States) isemployed. Both higher production rates and improved quality in the scionvariety are made possible. This provides the grower a significanteconomic advantage. The degree of increase has been found to beinfluenced by the scion variety in question and the cultivationconditions. Also, the new rootstock may make possible an acceptableyield at lower temperatures and the use of less artificial lighting.

A particularly advantageous increase in biomass has been observed whenthe scion variety is the ‘KORcut 0006’ variety (non-patented in theUnited States), the ‘KORsteimm’ variety (U.S. Plant Pat. No. 20,700),and the ‘KORcoluma’ variety (U.S. Plant Pat. No. 17,047). A lesseroverall biomass, and lesser stem length, commonly have been found to beexhibited when such scion varieties are grown on their own roots or on astandard ‘Natal Briar’ rootstock.

Filed concurrently herewith are two additional U.S. Plant patentapplications directed to other distinctive new rose rootstocks developedthrough the plant breeding and selection research of Applicant. Theseare U.S. Plant patent application Ser. No. ______ entitled RoseRootstock Named ‘Protatu’, and U.S. Plant patent application Ser. No.______ entitled Rose Rootstock Named ‘Protano’.

Standard DNA analysis using Simple Sequence Repeat (SSR) ormicrosatellites can be utilized to distinguish the new ‘Pronne’ cultivarfrom other rose varieties, including the ‘Protatu’ and ‘Protano’varieties. The presence or absence of eight standard markers with scoredalleles (i.e., RHB303, RHD221, RHE2A, RHI402, RHJ404, RHM405, RHO517,and RHP519) can be utilized and were evaluated with respect to the‘Pronne’, ‘Protatu’, and ‘Protano’ varieties as reported in the TABLEthat follows. This determination was carried out at StichtingNederlandse Algemene Kwaliteitsdienst Tuinbouw (Netherlands InspectionService for Horticulture), better known as Naktuinbouw. DNA from leafsamples of each cultivar was extracted using the standard NaktuinbouwCTAB DNA isolation protocol. The generated DNA fragments (alleles) wereseparated by gel electrophoresis. SSR DNA profiles were generated foreach variety. The generated DNA fragments (alleles) were separated bygel electrophoresis. The alleles were scored present or absent and arereported hereafter.

TABLE Marker RHB303 RHD221 RHE2A RHI402 RHJ404 RHM405 RHO517 RHP519‘Pronne’ H F B, D A, D D C, D C, D C ‘Protatu’ H F D A, E D B, D C, D C,F ‘Protano’ G, H F D A, B D C, D C, D C, FThe difference between ‘Pronne’ and ‘Protatu’ is 6 of the 53 alleles.The difference between ‘Pronne’ and Protano’ is 5 of the 53 alleles. Thedifference between ‘Protatu’ and ‘Protano’ is 5 of the 53 alleles. SeeG.D. Esselink, M.J.M. Smulders, and B. Voeman, “Identification of cutrose (Rosa hybrida) and rootstock varieties using robust sequence taggedmicrostallite site markers,” Theor Appl Genet, No. 106, Pages 277 to 286(2003).

The new variety of the present invention has been found to undergoasexual propagation beginning in 2008 at Overberg, The Netherlands, bythe rooting of stem cuttings. Asexual propagation by the above-mentionedtechnique has shown that the characteristics of the new variety arestable and are strictly transmissible by such asexual propagation fromone generation to another. Accordingly, the new variety undergoesasexual propagation in a true-to-type manner.

The new cultivar initially was designated ‘08-41’ and has been named‘Pronne’. At times, “PRO-4” has been associated with this cultivar.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying photographs show as nearly true as it is reasonablypossible to make the same, in color illustrations of this character,typical specimens of the plant parts of the new variety. The rose plantsof the new variety were approximately five years of age and wereobserved during June while growing outdoors on their own roots in sandysoil at Overberg, The Netherlands.

FIG. 1 illustrates typical foliage and buds and flowers of the newvariety in various stages of development. The fading of the initial pinkblossom coloration to near white upon maturity is depicted.

FIG. 2 illustrates a close view of a typical recently-opened pink flowerof the new cultivar wherein a profusion of orange reproductive parts isdisplayed at the center of the blossom. The presence of darkerpink/light red unopened buds also is depicted as is the finely serratedmargins of the foliage. Such serrations commonly are concentratedtowards the apex of the leaflets. Dimensions in centimeters are includedfor comparative purposes.

DETAILED BOTANICAL DESCRIPTION

The chart used in the identification of the colors is that of The RoyalHorticultural Society (R.H.S. Colour Chart—1995 edition or equivalent).The description is based on the observation of five-year-old plantsduring June while growing outside in sandy soil at Overberg, TheNetherlands.

-   Class: Most closely resembles Rosa multiflora.-   Plant:    -   -   Growth habit.—substantially upright.        -   Height.—commonly approximately 1.75 m on average.        -   Width.—commonly approximately 60 cm on average.-   Branches:    -   -   Internode length.—commonly approximately 4.8 cm on average.            Such internode length renders the plant well suited for            stenting as indicated hereafter.        -   Thorns.—commonly absent.-   Foliage:    -   -   Petioles.—length: approximately 12 mm on average. — diameter            approximately 1 mm on average. — texture: commonly smooth            and without small thorns.        -   Leaves.—length: commonly approximately 12 cm on average. —            width: commonly approximately 8 cm on average.        -   Leaflets.—number commonly 7 and 9. — shape: generally            elliptical with a somewhat acuminate tip and an obtuse base.            — size: the terminal leaflets commonly are approximately 50            mm in length on average, and approximately 27 mm in width on            average. — serration: small and fine and commonly            approximately 1 mm in size. Such serration tends to be            concentrated at approximately 50 percent of the margin of            each leaflet and is located at the tip. — texture: with a            matte upper surface.-   Inflorescence:    -   -   Number of flowers.—commonly borne in clusters.        -   Type.—single.        -   Time of flowering.—commonly commences in late June.        -   Peduncle.—length: commonly approximately 2.5 cm on average.            — diameter: commonly approximately 1 mm on average. —            texture: commonly slightly glandular.        -   Buds.—shape: substantially conical. — color commonly near            Red Group 52B and 52C.        -   Flower.—shape: cup-shaped. — diameter small, approximately            2.5 cm on average. — color (in the course of opening): upper            surface: near White Group 155A suffused with near Red Group            55D. under surface: near White Group 155A suffused with near            Red Group 55D. — color (mature open flower): upper side:            near White Group 155A. under side: near White Group 155A. —            fragrance: none detected. — petal number 5 under normal            growing conditions. — petal shape: generally heart-shaped. —            petal arrangement: somewhat imbricated, and without            petaloids. — stamen number approximately 80 on average. —            anthers: regularly arranged around the styles, orange in            coloration. — pollen: present, and near orange in            coloration. — pistils: fused. — stigmas: generally orange in            coloration. — styles: generally orange in coloration.-   Development:    -   -   Vegetation.—very strong.        -   Blooming.—commonly commences in late June.        -   Hardiness.—has well withstood −15° C. at Overberg, The            Netherlands.        -   Tolerance to diseases.—good, with no particular            susceptibility to common diseases having been encountered            during observations to date.        -   Asexual reproduction.—cuttings readily undergo rooting.        -   Use as understock.—stenting can be utilized when the new            variety serves as a rose understock for a scion rose            variety. In this instance, quick overall propagation can be            achieved by grafting the scion variety on an unrooted            cutting of the new variety. A resulting complete plant can            be formed thereafter in approximately three weeks. This            technique was developed by Peter A. van de Pol of Wageningen            Agricultural University (The Netherlands). The word            “stenting” is a contraction of the Dutch words “Stekken”            (rooting of a cutting) and “Enten” (grafting). The technique            and word were first published in 1979 in the Dutch Vakblad            voor de Bloemistenj, No. 26, Pages 40 to 41, and in English            in 1982, “Stenting of roses; A method for quick propagation            by simultaneously cutting and grafting,” Scientia            Horticulture, No. 17, Pages 187 to 196.

The new ‘Pronne’ variety has not been observed under all possibleenvironmental conditions to date. Accordingly, it is possible that thephenotypic expression may vary somewhat with changes in light intensityand duration, cultural practices, and other environmental conditions.

I claim:
 1. A new and distinct rose plant characterized by the followingcharacteristics: (a) displays an upright growth habit with vigorousgrowth, (b) forms small single pink changing to near white cup-shapedblossoms having five generally heart-shaped petals with the prominentdisplay of orange reproductive organs at the center of the blossoms, (c)exhibits medium green leaflets with finely serrated margins having amatte upper surface, and (d) when used as a rootstock for a cut rosescion variety exhibits a propensity to yield an increase in biomass andthe promotion of faster bud release for the scion variety; substantiallyas shown and described.